


the shape of you

by C Cohen (CCohen)



Category: The Mortal Instruments Series - Cassandra Clare
Genre: Alpha/Beta/Omega Dynamics, Dubious Consent, F/M, Mating Cycles/In Heat
Language: English
Status: Completed
Published: 2017-08-02
Updated: 2017-08-02
Packaged: 2018-12-10 09:38:36
Rating: Explicit
Warnings: Rape/Non-Con
Chapters: 1
Words: 1,460
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11688960
Author URL: https://archiveofourown.org/users/CCohen/pseuds/C%20Cohen
Summary: Clary knew she was in trouble when she woke up with a fever, cursing at herself for forgetting to get the vitamins when she ran away from home. However, oddly enough, it didn’t remind her of a normal cold. She felt hot all over, a ball of warmth in her core and heat clinging to her skin, an ache she couldn’t place plaguing her just as an weird emptiness that wasn’t hunger.





	the shape of you

Clary _knew_ she was in trouble when she woke up with a fever, cursing at herself for forgetting to get the vitamins when she ran away from home. However, oddly enough, it didn’t remind her of a normal cold. She felt hot all over, a ball of warmth in her core and heat clinging to her skin, an ache she couldn’t place plaguing her just as an weird emptiness that wasn’t hunger. Curiously enough, Clary was reminded of the lessons in heat she had, but that was weird - she wasn’t an Omega, she was a Beta. That was the only thing she was still certain on.

Maybe it was some weird fever, really. Clary sighed against her pillow, gooseflesh rising in her thighs, and wondered if maybe she could get away with sleeping all day.

“Clarissa?”, Sebastian knocked, and Clary groaned. Of course her nightmare of a brother _wouldn’t_ leave her alone. She had half a mind to tell him to go away, but for some reason, she didn’t. As if he missed on the cue to leave, Sebastian opened the door, and froze on the door, as if her glare had been able to do it. Good. “It smells sickeningly sweet in here.”

“Go away, I’m sick,”, she replied, sitting up. He smelled surprisingly nice. Was Sebastian in a rut? She only knew when Alphas were Alphas because she was able to smell their ruts out. Her damn sense of smell was took weak because she was a lowly Beta. “And if you’re going to go on a rut, get away from me.”

“You’re not sick, and I’m not in a rut.”, he moved from his spot, suddenly uncomfortable, closing the door behind him. Oh, great. “You, however, are in heat.”

Clary frowned, the smell of her brother overpowering her senses. He wasn’t supposed to smell so nice, so… Interesting.

Still, she shook her head. That wasn’t the subject at hand.

“That’s impossible. I’m a Beta.”, Clary replied, not noticing the way she was rubbing her thighs together, looking for some sort of friction. She felt warmer just looking at him.

Sebastian smirked, noticing what had passed right by her.

“The way you are says otherwise, Clarissa.”, was he _purring?_ That was sort of nice. Kind of hot, too. “If it smells like Omega, has a heat like a Omega, it’s probably an Omega. Unless…”

He sat near her, and Clary scooted closer, biting back her lower lip when Sebastian picked her chin slightly, raising her head and sniffing the curve of her neck. His hair tickled her sensitive skin, and it was rather nice. Too nice, perhaps. She put one hand in her thigh, scratching it mindlessly.

“Unless _what?”,_ Clary asked, trying to look defiant. She wasn’t sure it was working, not with the way Sebastian was so seemingly confident.

“You reek of chemicals, Clarissa,”, he hummed, warm breath against her skin making Clary shiver. “Vaguely, almost as if it was worked out of your system, but still _there_. Tell me, did mother dear give you some sort of pill?”

“She gave me vitamins, but she wouldn’t…”, purposefully withholding someone from presenting was a crime - not illegal, but definitely amoral. “Mom wouldn’t… Do _that_.”

His head rose, dark eyes against hers, his hand leaving her face, but the feeling remained there, scorching hot, hotter than her fever.

“Didn’t you not know about the Shadow World until a while ago, Clarissa? Aren’t you surprised mother lied to you once more?”, he purred, and the smirk on his face was dangerous, but Clary couldn’t muster enough of herself to scream for Jace. Besides, as much as Clary wanted to deny, he was right. “Now, let’s see what I have here. An unclaimed Omega, on her first heat, _defenseless_ . My, my, _my_.”

“Don’t you _dare_ ,”, Clary hissed, but his smirk only grew. Oh, he would. And Clary wouldn’t be able to do a damn thing, would she?

No - she wouldn’t. There was a fire in his eyes, burning, and the fuel was her heat.

“Too late, Clarissa,”, Sebastian replied, kissing her, one hand picking her by the wrists, holding her in place. Clary struggled a bit, for one moment, before Sebastian pinned her against the bed, towering over her lithe body, one knee opening her legs. Clary could feel herself losing the battle, getting soft with the way his tongue explored her mouth. By the Angel, he was good.

It was _maddening_ \- Clary could barely _think_ , the taste of Alpha pheromones thick on her tongue, making her feel wetness grow between her legs. Sebastian’s free hand wandered through her body, flicking over her lousy pajama shirt, cold air making her skin shiver. Sebastian let go of her mouth, a smirk playing on his lips.

“You’re _such_ a good girl, Clarissa,”, he purred, still holding her hands in place. She wanted to kick him, but there was just something _so nice_ about him holding her it made Clary sick. “Makes me want to fill you up alright. Wouldn’t you look nice, filled up with my pups?”

With his free hand, Sebastian started playing with her left breast, twisting her nipple slightly, making Clary have to bite back a moan as his knee pressed against her. She could feel herself going insane, grinding against him in search of friction, of _relief_ , trying fruitlessly to relieve herself of the ache that was building inside her.

Of _course_ , that only made Sebastian grin. The look on her face must’ve been great.

“What a nice little Omega you are, Clarissa.”, he slowly released her hands, and she kept them immobile as Sebastian’s now free hand wandered through her body, starting in her chin and going down, making her skin rise in gooseflesh. He stopped, for a moment, on the elastic band of her pajama shorts, but persisted, making Clary’s skin boil. He was _so close_ to where he should be, and yet, so far. “Makes one wonder if you can beg properly for a knot.”

What Clary wanted to say was a spat out _never._ What came out, when he started fingering her slowly, using his thumb to play with her clit, was a _barely_ repressed moan.

Sebastian smirked, slowing his rhythm, and Clary _whined,_ moving her hips.

“What should a pretty little Omega like you say, Clarissa, if you want more?”, Sebastian asked. Clary glared at him, but moaned when he inserted one more digit inside her, slowly moving, teasingly so - just enough to remind her of his fingers, but not enough to satisfy her.

“Please.”, Clary regretted every letter of the word, but she still felt so empty. She needed something _more,_ and only Sebastian had that.

“Please what?”, Sebastian hummed, starting to fiddle with his belt. Clary bit her lower lip, refusing to say what her mind screamed - and Sebastian, as if sensing it, rose one eyebrow, refusing to move. Clary whined, moving her hips, but he stayed quiet. “I can stay here all day.”

“ _Fine,”_ Clary hissed. Sebastian’s smirk only grew. How she hated him. “Please, Alpha.”

“What a good little Omega,” he said, kissing her once more, and _finally_ moving himself faster inside her, pumping his fingers in and out as if there were no tomorrow, her clit being roughly played with, but Clary didn’t mind - she was so sensible, it was pleasing, no matter out. Clary put her arms around his neck, deepening the kiss with a moan, and Sebastian’s laughter resonated through her as she came.

She felt a bit dirty - her brother had just made her cum, for the Angel’s sake! -, but Clary still felt unsatisfied. When he took his fingers from inside her, Clary moaned, needy, and all Sebastian did, separating from her lips, was laugh.

“Aw, the little Omega can’t take being empty, is that it?”, he asked, sing-song, mocking her. Clary would have answered, but she could hear Sebastian’s belt being unmade, and that was, somehow, the most interesting sound in the entire world. She rose her head, just in time to see his cock, Sebastian stroking it slowly.

The smell of pheromones grew thicker in the air, mixing with hers, sweet and spicy at the same time, and Clary sat down before she realized what she was doing, leaning into Sebastian to try and touch his growing erection. Sebastian smirked, and touched Clary’s face with careful fingers, and she looked in his dark eyes.

“Do you want this, Clarissa?”, he asked, but her mind was in a fog.

“Yes.”, Sebastian kept his firm touch, not moving an inch, and Clary blushed. “Yes, Alpha.”

“That’s a good Omega, Clarissa,”, he told her, kissing her softly and laying her in bed. Clary could barely wait, not noticing how she was losing her mind to the heat.


End file.
